Field of the Invention
The present invention relates to a sucking disc, in particular to a pad structure of the sucking disc.
Description of the Prior Art
In general, as shown in FIG. 6, a conventional sucking disc structure has a soft pad 80 commonly made of rubber, and the center of the pad 80 has a lifting portion 81, and a pressing member 82 is assembled above the pad 80. To use the sucking disc, firstly the pad 80 is attached onto a wall 9, and a control member 83 of the sucking disc is provided for controlling the pressing member 82 to press onto the pad 80. Next, the lifting portion 81 is lifted upward, so that the center position of the pad 80 is lifted upward. Since the pad 80 is already pressed onto the wall 9 and defines an airtight condition with the wall 9, when the lifting portion 81 is lifted upward, the pad 80 defines a vacuum space 84 with the wall 9, so that a strong suction is provided to fix the sucking disc onto the wall 9.
However, if air enters into the vacuum space 84, the suction will disappear since the vacuum condition is destroyed, and the sucking disc no longer has the effect of being fixed onto the wall 9. Therefore, the pressing ability of the pressing member 82 of the sucking disc to the pad 80 is very important. Because the pad 80 is made of soft material having the ability of being elastically deformed, when the pressing member 82 is controlled to press onto the pad 80 and to lift the lifting portion 81 upward, the force of the pressing member 82 applied to the pad 80 is still insufficient to resist against the deformation of the pad 80, and the periphery of the pad 80 would shift toward the center portion.
In addition, because the pressing member 82 is generally a thin casing, the area of the pad 80 to be pressed by the pressing member 82 is too small. On the other hand, as shown in FIG. 7, the top portion of the pad 80 is pressed by the pressing member 82 and deforms slightly, while the inner portion of the pad 80 is deformed apparently because its relative soft texture, and the farther distance the portion of the pad 80 is away from the top portion of the pad 80, the higher degree of deformation the portion of the pad 80 has. Consequently, the bottom portion of the pad 80 deforms significantly, the contact area between the pad 80 and the wall 9 is very small, and external air would enter into the vacuum space 84 to destroy the vacuum condition easily, so that the suction of the sucking disc would be failed.
The present invention is, therefore, arisen to obviate or at least mitigate the above mentioned disadvantages.